1. Field of the Invention
The present invention relates to a method for manufacturing a nano-template which is suitable for fabricating a high-density patterned medium and a high-density magnetic storage medium using the same.
2. Description of the Related Art
There is an increased demand for a record medium which is capable of storing mass information including moving pictures and has a high portability. It is also demanded that users who carry the record medium have an ability to access to and use the stored information.
Portable memory devices may be largely classified into a solid-state memory device such as a flash memory and a disk-type memory device such as a hard disk. Since the solid-state memory device is expected to be developed to have a maximum capacity of several gigabytes (GBs) in the next several years, it is difficult to use the solid-state memory device as a large scale data storage device. On the other hand, even though the hard disk mounted on a portable device is expected to have a capacity of several tens of GBs in the near future, it is also anticipated to be difficult to achieve magnetic recording density of more than the several tens of GBs.
In order to overcome such limitations, a method for manufacturing a large-capacity high-density patterned medium has been proposed. E.g., U.S. Pat. No. 7,041,394. U.S. Pat. No. 7,041,394 reports a method which includes forming a locking pattern in a medium substrate and filling the locking pattern with a magnetic particle having a size of less than 0.1 micrometer (i.e., less than 100 nanometer). The locking pattern is formed by lithography. In manufacturing a large-capacity high-density patterned recording medium, a use of a pattern template makes it possible to simplify the manufacturing process of the recording medium and increase a recording density of the medium.
A conventional template, which is used to manufacture a high-density patterned medium, will now be described.
FIG. 1 is a picture of a conventional template, which is used to manufacture a high-density patterned medium, and FIG. 2 is a picture of high-density patterned medium manufactured by using the template shown in FIG. 1.
As shown in FIGS. 1 and 2, a high-density patterned medium can be manufactured by forming a pattern 10, which is etched in a substrate, and by filling the pattern 10 with a nanomaterial 20. The pattern 10 may be formed by lithography. The nanomaterial may be chemically synthesized particles and completely fills the pattern.
The capacity of high-density patterned medium manufactured by using a conventional template, for example one reported in U.S. Pat. No. 7,041,394, depends on the size of a formed pattern 10. That is, as the size of the pattern 10 gets smaller, a higher-density patterned storage medium can be manufactured.
However, it is very difficult, with the current lithography technology, to form a fine pattern with a width of less than tens of nanometers. Particularly, it is difficult to form a fine pattern of nanometer size over a broad region of a large capacity by means of the electron beam or photo-lithography technology. It takes a long period of time to uniformly form a fine pattern in a broad region of a medium substrate and productivity is degraded, so that there is a limitation to use the lithography technology for mass production of the pattern and/or recording medium.